about RACH DOS

I am a student in a University studying on the security of GSM, recently I want use osmocomBB to realize the RACH DOS attack mentioned in Dieter Spaar`s speech. but I meet some difficulty. I do as follow: continuely sending RACH to a cell,and ignore the GSM48_MT_RR_IMM_ASS message ,also i lock my phone to the attacked cell,but after some time,the phone can still call to some phone ,why? can anyone help me? thanks! -- View this message in context: http://baseband-devel.722152.n3.nabble.com/about-RACH-DOS-tp3860492p3860492… Sent from the baseband-devel mailing list archive at Nabble.com.